168. Geo-electric response of the petiole of _Tropæolum_ 452 169. Geo-electric response of the scape of _Uriclis_ 453 170. Mechanical and electric response to indirect stimulation 463 171. Diagrammatic representation of mechanical and electric response of root 464 172. Diagrammatic representation of geo-electric response of root-tip 469 173. Diagrammatic representation of geo-electric response of growing region of root 471 174. Diagrammatic representation of the geo-perceptive layer 480 175. The Electric Probe 483 176. Transverse section showing continuous geo-perceptive layer (_Bryophyllum_) 488 177. Curve of geo-electric excitation in different layers of _Nymphæa_ 497 178. Curve of geo-electric excitation in _Bryophyllum_ 497 179. Diagram of arrangement of geotropic torsional response 503 180. Additive effect of stimulus of gravity and light 505 181. Algebraical summation of geotropic and phototropic actions 505 182. Comparative balancing effects of white and red lights 506 183. Effect of coal gas on photo-geotropic balance 507 184. Diagram of magnetic balance 511 185. Effect of variation of light on phototropic equilibrium 512 186. Effect of variation of temperature on geotropic torsion 514 187. Simultaneous records of variation of temperature, on up and down movement, and of torsion of the leaf of _Mimosa_ 518 188. Arrest of pulsatory movement of leaflet of _Desmodium gyrans_ by light 528 189. Effect of unilateral light on hyponastic movement 529 190. The Nyctitropic Recorder 537 191. Effect of sudden darkness on leaflet of _Casia alata_ 539 192. Diurnal movement of the leaflet of _Cassia alata_ 540 193. The day and night position of the petiole and terminal leaflet of _Desmodium gyrans_ 541 194. Diurnal record of the terminal leaflet of _Desmodium gyrans_ 542 195. Photograph of closed flower of _Nymphæa_ during day 550 196. Photograph of open flower of _Nymphæa_ at night 550 197. Action of light on the petal of _Nymphæa_ 551 198. Diurnal movement of the petal of _Nymphæa_ 552 199. Diurnal record of the Sijbaria Palm 556